The limo bus, which was carrying Morgan and six others, overturned at around 1 a.m. Saturday morning near Cranbury Township, Sgt. First Class Greg Williams of the New Jersey State Police told The Associated Press. The accident involved six vehicles, including two tractor trailers and an SUV.

One of the tractor trailers crashed into the limo bus, state police told The New York Times. The driver of the truck didn't notice that traffic ahead of him had slowed until it was too late, police told ABC News. The truck hit the limo bus from behind, sending it crashing into other vehicles before tipping over on its side, ABC reported. The Associated Press reports that the truck driver involved in the incident has been charged with causing the crash.

James McNair, one of Morgan's comedy writers who was also riding in the limo bus, was killed. He was 62.

Morgan, 45, is in intensive care at Robert Wood Johnson Medical Center in New Brunswick, NJ. The father of four is known for his roles on "Saturday Night Live" and "30 Rock."

"Tracy remains in critical condition at Robert Wood Johnson Hospital," Morgan's representative, Lewis Kay, said in a statement. "He sustained these injuries in an accident that occurred early this morning as one of several passengers in a chauffeured SUV returning from a tour date in Delaware. His family is now with him and he is receiving excellent care. We don't anticipate much of a change in his condition today but will provide a further update once more information becomes available."

The actor's ex-wife, Sabina Morgan, told the New York Daily News that Morgan was unconscious and has a broken leg. Doctors assured her that he is expected to recover, she told the News.

Morgan gave a standup show in Dover, Delaware on Friday night. Fuqua, who opened for Morgan, posted a photo of the event to Instagram:

Williams said the tractor-trailer driver apparently failed to notice slow traffic ahead and swerved at the last minute in a vain attempt to avoid a crash. But it smashed into the back of the limo, prompting a chain-reaction crash with a second tractor-trailer, an SUV and two cars.

The National Transportation Safety Board said it was working with state police to look at any issues in the crash related to commercial trucking and limousine safety.

Morgan's limo was owned by Atlantic Transportation Services, which said it had one employee behind the wheel and a second in the front passenger seat.

"Although the investigation is still pending, we concur with the preliminary reports that the accident was caused by another vehicle traveling behind the Atlantic limo bus," the Rehoboth Beach, Delaware-based company said. "We are grateful that our drivers did not sustain life-threatening injuries."

Morgan performed comedy standup Friday night at Dover Downs Hotel & Casino. His scheduled appearance at the Fillmore Charlotte in North Carolina on Saturday night was canceled.

Fuqua had tweeted that he was opening for Morgan on Friday. On his Instagram page, Fuqua included a collage of photos from the Delaware show.

"This is what it looks like from the stage to see a standing ovation from 1500 people," Fuqua wrote at around midnight Friday. "Then we traveled back to NYC in style in a luxury Mercedes Sprinter. Road life is a good life!"

Morgan, a New York City native, joined "SNL" in 1996 and was on the sketch-comedy program for seven years before leaving to star in "The Tracy Morgan Show" in 2003. That show lasted just one season. In 2006, Morgan found a long-running role on NBC's hit show "30 Rock," which was created by "SNL" co-star Tina Fey. He received an Emmy nomination for best supporting actor for "30 Rock" in 2009.

Morgan grew up fatherless, one of five siblings, in a blighted section of Brooklyn, where he helped raise and support the family.

He once called his gift for being funny "a defense mechanism" for his miserable circumstances. As a teen, he started doing comedy on the streets to supplement the family's welfare income.

His tough upbringing informed his humor.

"My aunt was a crackhead," he told his Brooklyn audience in a recent special aired on Comedy Central. "I remember one Christmas she bought me a Game Boy. Then she stole it. Then she helped me look for it."

In recent years, he has struggled with alcoholism and drunken driving arrests. He had a successful kidney transplant in late 2010.

UPDATE: [7:48 p.m. ET] - In a statement, Walmart President Bill Simon said that a Walmart truck was involved in the crash and that the company "will take full responsibility" if it is determined that the Walmart truck caused the accident.